100 years ago. each day, 750,000 people pour through grand central. what do you think, grand central, 100 years old? >> i think it's fantastic. >> we love grand central, never looked better. >> there is poetry in this place. it is a worm, inviting place for something as large and cathedral-like. >> reporter: the construction of grand central paved the way for multilevels of track service. and soon the era of luxury train travel arrived. but as plane travel soared and the railways ran into bankruptcy, grand central was nearly demolished. civic fight led by a former u.s. first lady helped save grand central. >> if you destroy your past, something in people die. >> reporter: now in a new york minute you can spot a wedding, a modeling shoot -- >> it's absolutely stunning. >> reporter: and a squash tournament. >> with these mysteries and things -- >> reporter: tour guide dan bruker revealed the secrets of grand central. look up, people don't even notice a ceiling to mirror the constellation. >> move, move, chop, chop, in the corn,er, let's go!